Pope Benedict XVI stunned the Vatican on Monday, saying he no longer has the strength to do the job.

The 85-year-old Pontiff said he will step down at the end of the month.

Benedict became head of the Catholic church in 2005, succeeding Pope John Paul II.

He tackled the priest abuse scandal, apologizing to victims and acknowledging the church's mistakes, but some say he didn't go far enough.

Pope Benedict appointed more than half the cardinals who will choose his successor.

The Vatican hopes to have a new pope in time for Easter at the end of March.

While Louisville Archbishop Joseph Kurtz tried to answer many questions Monday, there's still so much unknown, since it has been nearly 600 years since a pope has resigned and Kurtz said there is no formality guide book on how to handle the situation.

"That's forging new ground in many ways," said Kurtz.

"I was really surprised in our lifetime it's never happened. It's been a long time," said Catholic Pat Hagerty.

"I'm not sure there would be a history that would actually capture what he did today," said Kurtz.

Kurtz addressed the shocking news that has sparked several questions, like what the outgoing pope's title will be, or how he will interact with the new pope?

"The most interesting thing is going to be who they do designate as the candidate," said Hagerty.

"I suspect whoever is appointed will be younger," said Kurtz.

That's one safe assumption since the now 85-year-old pope said he's resigning because of his health.

He said carrying out the duties of being pope requires both strength of mind and body, which have both deteriorated to the point he can no longer fulfill his ministry.

"He recognizes its time for him to step aside and someone who has more energy and better health in a better position to lead the church," said Catholic Bill Ferko.

As far as who that someone might be, Kurtz didn't have anyone in particular in mind.

"Who are the candidates? Cardinals who would be of holiness, of experience pastorially," said Kurtz.

While the pope's resignation will be final at the end of this month, he said he hopes to continue to serve in the future through prayer.

Pope Benedict also drew a lot of attention when he started tweeting months ago. Kurtz said the new pope will, likely, also be active on Twitter.